Cannon-pinion shaft.



W. B. MEHL. CANNON PINION SHAFT. APPLIUATION FILED AUG. e, 1909.

Patented Mar. 8, 1910.

UNl'iE STATES PAT il FICE@ WALTER BIRD MEHL, OF WALTHAM, MASSACHUSETTS, ASSIGNOR TO PHILADELPHIA l VVAICI-I CASE COBIPANY, OE RIVERSIDE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

To all whom it may concern:

Be it known that I, VALTER BIRD Min-Hi, a citizen of the United States, and a resident of Valtham, in the county of Middlesex and State of Massachusetts, have mad-e and invented certain new and useful Improvements in Cannon-Pinion Shafts, of which the following is a specification.

This invention relates to an improvement in watch movements, and more particularly to a novel construction of a cannon pinion shaft. Heretofore in forming this shaft it has been the practice to construct the saine of solid metal throughout its entire length, and to slit th-e same down through the center, part way of its length, thereby forming two spring lingers of equal proportions or dimensions. It has been found, however, that such form of shaft has been unsatisfactory, in that in many instances, the alinementof the shaft through the center pinion has been destroyed, one of the spring arms having more resiliency than the other.

The purpose of my invention is to overcome this objection and to provide a shaft, the alinement of which will always be preserved, and with this and other ends in view consists in certain novel features of construction and combination of parts as will be hereinafter fully described.

in the accompanying drawings Figure l is a plan view of a part of a watch movement, showing my improved cannon pinion as appli-ed thereto. Fig. 2 is a sectional view thereof taken on the line Q-2 of Fig. l. Fig. 3 is detached view in perspective of a cannon pinion shaft constructed in accordance with my invention.

Referring to the drawings, 4 represents the center pinion, the ends of which have their bearings in the top plate 5, and dial plate 6. Through the center pinion 4 passes the cannon pinion shaft 7 on which is fric- Specication of Letters Patent.

Application filed August 6, 1909.

Patented Mar. 8, 1910.

Serial No. 511,485.

tioned the cannon pinion 8, this shaft being hollowed out for a portion of this length, and slotted as illustrated in Fig. 3, whereby to form a spring tongue or arm 9 and a rigid arm l0, the length of the spring arm 9 being substantially equal to that of the hollowed out portion, and in circumference about one third that of the shaft. rihis form of shaft I have found in practice to be a great improvement over the old type, in that while the spring member 9 is of sufficient. dimension to frictionally retain the shaft within the pinion 4, and otherwise perform its functions, the shaft as a whole will always retain its proper alinement by reason of the' bearing surface contained 7ithin the two thirds of its unslitted circumference. It will also be understood that the tension of the spring member 9 will be increased or decreased by bending the same toward or away from the remaining rigid portion 10, and this without in anywise endangering the alinement of the shaft.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is ln watch movement, the combination with a top plate and a dial plate, of a center pinion mounted between said plates, and a cannon pinion shaft passing through said center pinion, said shaft being hollowed out for a portion of its length and slotted to form a spring tongue of approximately one third of the circumference of said shaft, substantially as described.

Signed at lWaltham, in the county of Middlesex and State of Massachusetts, thisI 2nd day of August A. D. 1909.

WALTER BIRD MEI-IL.

R. SCHMIEDTZEN. 

